Hello Akshay, welcome to IBB Forum.
The good news is that, India has finally risen up to the need for eco-friendly cars and manufacturers have now spoilt us for choice. You can now get everything from a small car, a hatchback to even an MPV with an option of CNG. The smallest CNG car in India is the Tata Nano. Under the hood, Tata Nano CNG houses the 624 cc, water-cooled, two cylinder engine developing 32 bhp in CNG mode and 37 bhp in petrol mode.
The best part is, it comes at a price of only about Rs. 2.69 lakhs. Tata has indeed done a fabulous job in fitting the CNG tank in the mini hatchback, given the petite size of the car. In fact, the vehicle can sense when the driver needs more power, and thus, can automatically shift to petrol mode. Thanks to a push-button fuel type selector, you can effortlessly switch between CNG and petrol driving modes on-the-go.